1. Field of the Invention
The present invention relates to a camera capable of performing a flash bracketing photo-taking operation.
2. Description of Related Art
The flash bracketing function is a function of increasing or decreasing the amount of flash light emission by a desired amount with respect to a predetermined (apposite) amount of flash light emission, for each shot to be taken by flash photography. In the meantime, some of known cameras are arranged such that, in carrying out flash photography, if the actual charge voltage of a flash device is lower than a minimum voltage at which flash light emission is possible (hereinafter referred to as a light emission enabling voltage), a photo-taking operation is carried out using only external available light without using the flash device when a shutter release operation is performed. In the case of a camera arranged to perform a photo-taking operation without using a flash device (hereinafter referred to as non-flash photo-taking) when a charge voltage of the flash device drops to a level lower than the light emission enabling voltage while the flash bracketing photo-taking is in process, the photo-taking operation is carried out using only external light without using the flash device.
In the event of such a non-flash photo-taking operation in the flash bracketing photo-taking operation, the continuity of the amount of flash exposure would be lost before completion of one sequence of flash bracketing, assuming that one sequence of flash bracketing consists of, for example, three shots.
Meanwhile, some cameras have an FE lock function. The FE lock function is a function of establishing a basic light emitting amount (the amount of main light emission) of a flash device in the case of photo-taking with a preliminary light emission from the flash device before commencement of a sequence of photo-taking actions. It has been practiced to use the FE lock function and the flash bracketing function separately from each other.
According to the conventional arrangement of the FE lock function, when the charge voltage of the flash device becomes lower than the light emission enabling voltage, it is impossible to carry out flash photography. Therefore, in that event, it has been practiced to cancel the FE lock function by clearing information related to the FE lock function (FE lock information).
However, in a case where both the FE lock function and the flash bracketing function are used at a time, if the FE lock information is cleared when the charge voltage of the flash device becomes lower than the light emission enabling voltage, the process of flash bracketing in the state of FE lock tends to come to an end before its completion.
Further, if the flash bracketing process is allowed to continue after updating the information related to the FE lock function during the flash bracketing process, the continuity of the amount of flash exposure for one sequence of flash bracketing would be lost.